The search for a permanent electric dipole moment
of an elementary particle, or a composite system of
particles
(see [1]}, or a recent
reference [2]} for a review),
is a challenge, not only for experiments, but also for theories
of composite systems.
Heavy atoms are excellent examples
of composite systems with large EDMs, due to the existence
of mechanisms which may induce atomic EDMs several orders
of magnitude larger than an intrinsic particle EDM.
In the present paper we computed the EDMs of three diamagnetic
atoms,
\(^{225}\) Ra, \(^{199}\) Hg, and \(^{171}\) Yb.
The purpose of the present paper is fourfold.
Firstly, we tested the newly developed
programs to evaluate
matrix elements of \((P,T)\) -odd e-N
tensor-pseudotensor and pseudoscalar-scalar interactions,
the atomic electric dipole interaction,
the nuclear Schiff moment, and the interaction of the electron electric dipole
moment with nuclear magnetic moments.
Secondly,
we generated the atomic wave functions in several different approaches,
in order to test the dependence of the calculated atomic EDMs
on options available in the GRASP2K [3]} implementation
of the MCDHF method.
The approaches depended on the choice of variational energy functional
(Average Level versus Optimal Level,
with different numbers of optimised levels),
the choice of wave functions built on a common orbital set or several separately optimised orbital sets,
in the latter case biorthogonal transformations of wave functions
had to be applied,
as well as on specific methods of one-electron orbital generation.
All these approaches are discussed in more detail in
section REF , REF , REF  and
REF 
and presented in Tables
REF ,
REF , and
REF .
Thirdly,
we sequentially generated several layers of virtual
(correlation) orbitals
for each of the three elements
and observed the effects of electron correlation on atomic EDMs.
All valence and core-valence electron correlation effects were
included through single and restricted double electron substitutions
from core-valence to virtual orbitals.
And finally, we provide independently calculated
atomic EDMs in
\(^{225}\) Ra, \(^{199}\) Hg, and \(^{171}\) Yb,
and compare our results with those of other authors.
Our results,
presented in the
Tables REF ,
REF ,
REF , and
REF ,
were obtained within the
multiconfiguration Dirac-Hartree-Fock (MCDHF) method,
using the relativistic atomic structure package GRASP2K [3]},
which, to the best of our knowledge,
and with the exception of one paper [5]}
on the Schiff moment in radium,
has been employed for the first time
in the calculations of
matrix elements of \((P,T)\) -odd e-N
tensor-pseudotensor and pseudoscalar-scalar interactions,
nuclear Schiff moment, and interaction of electron electric dipole
moment with nuclear magnetic moments.
